| Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof -> Monitor Keywords |
|
|
  Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereofUSPTO Application #: 20060201614Title: Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof Abstract: A method for producing a polycarbonate article having improved ultraviolet protection, the method comprising extruding a substrate comprising polycarbonate; impregnating an ultraviolet radiation absorber into a surface of the substrate to form an interlayer; and laminating a weatherable film onto the interlayer of the substrate. This method allows a weatherable acrylic film to be uniformly applied to the substrate to provide long term anti-yellowing performance. Articles made by this dual-layer process have excellent weathering performance for extended periods of time and can be employed in the production of commercial signs. (end of abstract) Agent: Cantor Colburn, LLP - Bloomfield, CT, US Inventors: Charles Mulcahy, Safwat Tadros, Mao Chen, Scott Turner USPTO Applicaton #: 20060201614 - Class: 156244110 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20060201614. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 10/290,431, filed on Nov. 07, 2002, which is related to and claims priority from Provisional Application No. 60/344,267 filed on Dec. 27, 2001, the entire contents of both of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] This disclosure relates to articles comprising polycarbonate resins, and in particular to articles and methods for ultraviolet light protection of such articles. [0003] Polycarbonate resins, are widely used as transparent glazing materials for windows, windshields, and the like. While polycarbonate resins are easily fabricated into desired shapes and have excellent physical and chemical properties, they have relatively low abrasion and chemical solvent resistance, and like many other organic polymeric materials are subject to degradation by ultraviolet radiation. Degradation of polycarbonate articles by ultraviolet radiation may occur when polycarbonate resins are used in applications that are subjected to environmental conditions, such as signs for shopping and commercial areas. Such signs, which often comprise a layer of white polycarbonate, can be particularly vulnerable to yellowing. [0004] One approach to protecting polycarbonate articles from environmental effects and ultraviolet radiation has been to impregnate the surface of the articles with an ultraviolet light absorbing compound. However, the surface impregnation may be too thin to provide the desired long-term stability. Another approach is to co-extrude the polycarbonate article and a weatherable film. Ultraviolet light protection may be provided by incorporating an ultraviolet light absorber into the polycarbonate melt or the weatherable film, or by co-extruding an intermediate layer between the polycarbonate article and the weatherable film, wherein the intermediate layer comprises an ultraviolet light absorber. Co-extrusion, however, has several drawbacks, chief amongst them being the lack of uniformity of thickness of the weatherable film and the ultraviolet radiation-absorbing layer. This leads to sporadic yellowing as well as a shortened life for the polycarbonate article. There accordingly exists a need in the art for laminates and laminated articles wherein the thickness of the weatherable layer as well as the layer of ultraviolet radiation absorbing layer applied to the polycarbonate is uniform, thereby reducing defects. BRIEF DESCRIPTION OF THE FIGURES [0005] The FIGURE is a schematic representation of a polycarbonate article, interlayer, and weatherable film. SUMMARY OF THE INVENTION [0006] A method for producing a polycarbonate article having improved ultraviolet protection, comprises: impregnating an ultraviolet radiation absorber into a surface of the substrate to form an interlayer; and laminating a weatherable film onto the interlayer of the substrate. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0007] It has been unexpectedly discovered that an article created from a laminate, wherein the laminate comprises a weatherable film applied to a substrate comprising polycarbonate resin impregnated with a uniformly thick layer of ultraviolet radiation absorbing material can withstand ultraviolet radiation without yellowing for extended periods of time. The use of a roll coater to apply the ultraviolet radiation absorbing material allows for uniform application of this layer onto the substrate. In addition, the use of a preformed weatherable film of uniform thickness applied to the coated substrate by a calendaring roll permits a laminate wherein each of the layers is substantially uniform in thickness, thereby avoiding the sporadic or spotty yellowing that is found in similar products produced by co-extrusion. This method is especially useful in producing signs for use in shopping and commercial establishments, which are continually subjected to the elements of the environment. [0008] The polycarbonate resin comprises aromatic carbonate chain units and includes compositions having structural units of the formula (I): in which at least about 60 percent of the total number of R.sup.1 groups are aromatic organic radicals and the balance thereof are aliphatic, alicyclic, or aromatic radicals. Preferably, R.sup.1 is an aromatic organic radical and, more preferably, a radical of the formula (II): -A.sup.1-Y.sup.1-A.sup.2- (II) wherein each of A.sup.1 and A.sup.2 is a monocyclic, divalent aryl radical and Y.sup.1 is a bridging radical having one or two atoms which separate A.sup.1 from A.sup.2. In an exemplary embodiment, one atom separates A.sup.1 from A.sup.2. Illustrative non-limiting examples of radicals of this type are --O--, --S--, --S(O)--, --S(O.sub.2)--, --C(O)--, methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecylidene, cyclododecylidene, and adamantylidene. The bridging radical Y.sup.1 can be a hydrocarbon group or a saturated hydrocarbon group such as methylene, cyclohexylidene or isopropylidene. [0009] Polycarbonate resins can be produced by the reaction of the carbonate precursor with dihydroxy compounds. Typically, an aqueous base such as (e.g., sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like,) is mixed with an organic, water immiscible solvent such as benzene, toluene, carbon disulfide, or dichloromethane, which contains the dihydroxy compound. A phase transfer resin is generally used to facilitate the reaction. Molecular weight regulators may be added to the reactant mixture. These molecular weight regulators may be added singly or as a combination. Branching resins, described forthwith may also be added singly or in admixture. Another process for producing aromatic polycarbonate resins is the transesterification process, which involves the transesterification of an aromatic dihydroxy compound and a diester carbonate. This process is known as the melt polymerization process. The process of producing the aromatic polycarbonate resins is not critical. [0010] As used herein, the term "dihydroxy compound" includes, for example, bisphenol compounds having general formula (III) as follows: wherein R.sup.a and R.sup.b each represent a halogen atom, for example chlorine or bromine, or a monovalent hydrocarbon group, preferably having from 1 to 10 carbon atoms, and may be the same or different; p and q are each independently integers from 0 to 4; Preferably, X.sup.a represents one of the groups of formula (IV): wherein R.sup.c and R.sup.d each independently represent a hydrogen atom or a monovalent linear or cyclic hydrocarbon group and R.sup.e is a divalent hydrocarbon group. [0011] Some illustrative, non-limiting examples of suitable dihydroxy compounds include the dihydroxy-substituted aromatic hydrocarbons disclosed by name or formula (generic or specific) in U.S. Pat. No. 4,217,438, which is incorporated herein by reference. A nonexclusive list of specific examples of the types of bisphenol compounds that may be represented by formula (III) includes 1,1-bis(4-hydroxyphenyl) methane; 1,1-bis(4-hydroxyphenyl) ethane; 2,2-bis(4-hydroxyphenyl) propane (hereinafter "bisphenol A" or "BPA"); 2,2-bis(4-hydroxyphenyl) butane; 2,2-bis(4-hydroxyphenyl) octane; 1,1-bis(4-hydroxyphenyl) propane; 1,1-bis(4-hydroxyphenyl) n-butane; bis(4-hydroxyphenyl) phenylmethane; 2,2-bis(4-hydroxy-1-methylphenyl) propane; 1,1-bis(4-hydroxy-t-butylphenyl) propane; bis(hydroxyaryl) alkanes such as 2,2-bis(4-hydroxy-3-bromophenyl) propane; 1,1-bis(4-hydroxyphenyl) cyclopentane; and bis(hydroxyaryl) cycloalkanes such as 1,1-bis(4-hydroxyphenyl) cyclohexane. Two or more different dihydric phenols may also be used. [0012] Typical carbonate precursors include the carbonyl halides, for example carbonyl chloride (phosgene), and carbonyl bromide; the bis-haloformates, for example the bis-haloformates of dihydric phenols such as bisphenol A, hydroquinone, and the like, and the bis-haloformates of glycols such as ethylene glycol and neopentyl glycol; and the diaryl carbonates, such as diphenyl carbonate, di(tolyl) carbonate, and di(naphthyl) carbonate. [0013] Typical branching resins such as .alpha.,.alpha.,.alpha.',.alpha.'-tetrakis(3-methyl-4-hydroxyphenyl)-p-xy- lene, .alpha.,.alpha.,.alpha.',.alpha.'-tetrakis(2-methyl-4-hydroxyphenyl)- -p-xylene, .alpha., .alpha.,.alpha.',.alpha.'-tetrakis(2,5dimethyl-4-hydroxyphenyl)-p-xylene, .alpha.,.alpha.,.alpha.',.alpha.'-tetrakis(2,6dimethyl-4-hydroxyphenyl)-p- -xylene, .alpha.,.alpha.,.alpha.',.alpha.'-tetrakis(4-hydroxyphenyl)-p-xyl- ene, trimellitic acid, trimellitic anhydride, trimellitic trichloride, tris-p-hydroxy phenyl ethane, isatin-bis-phenol, tris-phenol TC (1,3,5-tris((p-hydroxyphenyl)isopropyl)benzene), tris-phenol PA (4(4(1,1-bis(p-hydroxyphenyl)-ethyl)alpha, alpha-dimethyl benzyl)phenol), 4-chloroformyl phthalic anhydride, trimesic acid, benzophenone tetracarboxylic acid and the like, can also be added to the reaction mixture. Blends of linear polycarbonate and branched polycarbonate resins can be utilized herein. The branching agent may be added at a level of about 0.05 to about 2.0 weight percent (wt %). [0014] Some illustrative, non-limiting examples of suitable phase transfer resins include, but are not limited to, tertiary amines such as triethylamine, quaternary ammonium compounds, and quaternary phosphonium compounds. [0015] Molecular weight regulators or chain stoppers are optional and are added to the mixture in order to arrest the progress of the polymerization. Typical molecular weight regulators such as phenol, chroman-1, p-t-butylphenol, p-bromophenol, para-cumyl-phenol, and the like may be added either singly or in admixture and are generally added in an amount of about 1 to about 10 mol % excess with respect to the BPA. The molecular weight of the polycarbonate resin is generally greater than or equal to about 5000, preferably greater than or equal to about 10,000, more preferably greater than or equal to about 15,000 g/mole. In general it is desirable to have the polycarbonate resin less than or equal to about 100,000, preferably less than or equal to about 50,000, more preferably less than or equal to about 30,000 g/mole as calculated from the viscosity of a methylene chloride solution at 25.degree. C. [0016] The polycarbonate resin may, optionally, further comprise one or more other thermoplastic resins in addition to the aromatic polycarbonate resin, such as, for example, polyphenylene ether resins, vinyl aromatic graft copolymer resins, styrenic resins, polyester resins, polyamide resins, polyesteramide resins, polyetheresteramide resins, vinyl aromatic graft copolymer such as acrylonitrile-butadiene-styrene, polysulfone resins, polyimide resins, and polyetherimide resins. In another embodiment, in the event that a blend of the polycarbonate resin with an optional polyester or any of the other above listed thermoplastic resins is employed as the substrate, it is then desirable for the polycarbonate resin to be present in an amount greater than or equal to about 30, preferably greater than or equal to about 40 wt % of the substrate composition. It is also desirable for the polycarbonate resin to be present in an amount of about 100, preferably less than or equal to about 90, more preferably less than or equal to about 80 wt % of the substrate composition. [0017] The polycarbonate resin or polycarbonate resin blend is generally extruded in the form of a sheet. The thickness of the sheet is greater than or equal to about 0.5, preferably greater than or equal to about 100, more preferably greater than or equal to about 200, most preferably greater than or equal to about 1000 microns. In general it is desirable for the sheet to have a thickness less than or equal to about 15 millimeters (mm), preferably less than or equal to about 12 mm, more preferably less than or equal to about 10 mm (10,000 microns). [0018] The ultraviolet radiation absorbers for use in the invention have the ability to screen out the damaging ultraviolet portion of light. These compounds include the benzophenones, benzotriazoles, benzoate esters, phenyl salicylates, crotonic acid, malonic acid esters, cyanoacrylates, derivatives, and combinations comprising any one of the foregoing ultraviolet radiation absorbers. [0019] Included among the ultraviolet radiation absorbers, which fall into the categories of benzophenone derivatives and benzotriazole derivatives are those compounds disclosed in U.S. Pat. Nos. 3,309,220, 3,049,443 and 2,976,259, all of which are herein incorporated by reference. Some non-limiting examples of these compounds include: 2,2'-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-diethoxybenzophenone, 2,2'-dihydroxy-4,4'-dipropoxybenzophenone, 2,2'-dihydroxy-4,4'-dibutoxybenzophenone, 2,2'-dihydroxy-4-methoxy-4'-ethoxybenzophenone, 2,2'-dihydroxy-4-methoxy-4'-propoxybenzophenone, 2,2'-dihydroxy-4-methoxy-4'-butoxybenzophenone, 2,2'-dihydroxy-4-ethoxy-4'-propoxybenzophenone, 2,2'-dihydroxy-4-ethoxy-4'-butoxybenzophenone, 2,3'-dihydroxy-4,4'-dimethoxybenzophenone, 2,3'-dihydroxy-4-methoxy-4'-butoxybenzophenone, 2-hydroxy-4,4',5'-trimethoxybenzophenone, 2-hydroxy-4,4',6'-tributoxybenzophenone, 2-hydroxy-4-butoxy-4',5'-dimethoxybenzophenone, 2-hydroxy-4-ethoxy-2',4'-dibutylbenzophenone, 2-hydroxy-4-propoxy-4',6'-dichlorobenzophenone, 2-hydroxy-4-propoxy-4',6'-dibromobenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-ethoxybenzophenone, 2-hydroxy-4-propoxybenzophenone, 2-hydroxy-4-butoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxy-4'-ethylbenzophenone, 2-hydroxy-4-methoxy-4'-propylbenzophenone, 2-hydroxy-4-methoxy-4'-butylbenzophenone, 2-hydroxy-4-methoxy-4'-tertiarybutylbenzophenone, 2-hydroxy-4-methoxy-4'-chlorobenzophenone, 2-hydroxy-4-methoxy-2'-chlorobenzophenone, 2-hydroxy-4-methoxy-4'-bromobenzophenone, 2-hydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4,4'-dimethoxy-3-methylbenzophenone, 2-hydroxy-4,4'-dimethoxy-2'-ethylbenzophenone, 2-hydroxy-4,4',5'-trimethoxybenzophenone, 2-hydroxy-4-ethoxy-4'-methylbenzophenone, 2-hydroxy-4-ethoxy-4'-ethylbenzophenone, 2-hydroxy-4-ethoxy-4'-propylbenzophenone, 2-hydroxy-4-ethoxy-4'-butylbenzophenone, 2-hydroxy-2-hydroxy-4-ethoxy-4'-propoxybenzophenone, 2-hydroxy-4-ethoxy-4'-butoxybenzophenone, 2-hydroxy-4-ethoxy-4'-chlorobenzophenone, 2-hydroxy-4-ethoxy-4'-bromobenzophenone, 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)-benzotriazole, 2-(2'-hydroxy-3 '-methyl-5'-tert-butylphenyl)-benzotriazole, 2-(2'-hydroxy-5'-cyclohexylphenyl)-benzotriazole, 2-(2'-hydroxy-3',5'-dimethylphenyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-di-tert-butylphenyl)-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3.alpha.-cumyl-5-tert-octylphenyl)-2H-benz- otriazole, 5-trifluoromethyl-2-(2-hydroxy-5-tert-octylphenyl)-2H-benzotria- zole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotria- zole, 2'-methylene-bis [6-(5-trifluoromethyl-2H-benzotriazol-2-yl)-4-tert-octylphenol], methylene-2-[4-tert-octyl-6-(2H-benzotriazol-2-yl) phenol]2'-[4-tert-octyl-6-(5-trifluoromethyl-2H-benzotriazol-2-yl)phenol]- , 3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydroci- nnamic acid, methyl 3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocin- namate, isooctyl 3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyhydrocin- namate, 5-trifluoromethyl-2-[2-hydroxy-5-(3-hydroxypropyl)phenyl]-2H-benzo- triazole, 5-butylsulfonyl-2-(2-hydroxy-3-.alpha.-cumyl-5-tert-octylphenyl)- -2H-benzotriazole, 5-octylsulfonyl-2-(2-hydroxy-3,5-di-tert-cumylphenyl)-2H-benzotriazole, 5-dodecylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole, 5-octylsulfonyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3-tert-cumyl-5-tert-butylphenyl)-2H-benzot- riazole, 5-trifluoromethyl-2-(2-hydroxy-3-.alpha.-cumyl-5-nonylphenyl)-2H-- benzotriazole, 5-trifluoromethyl-2-[2-hydroxy-3-.alpha.-cumyl-5-(2-hydroxyethyl)phenyl]-- 2H-benzotriazole, 5-trifluoromethyl-2-[2-hydroxy-3-.alpha.-cumyl-5-(3-hydroxypropyl)phenyl]- -2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-amylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3-dodecyl-5-methylphenyl)-2H-benzotriazole- , 5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(3-hydroxypropyl)phenyl]-2- H- benzotriazole, 5-trifluoromethyl-2-[2-hydroxy-3-tert-butyl-5-(2-hydroxyethyl)phenyl]-2H-- benzotriazole, 5-trifluoromethyl-2-[2-hydroxy-5-(2-hydroxyethyl)phenyl]-2H-benzotriazole- , 5-trifluoromethyl-2-(2-hydroxy-3,5-di-.alpha.-cumylphenyl)-2H-benzotriaz- ole, 5-fluoro-2-(2-hydroxy-3,5-di-.alpha.-cumylphenyl)-2H-benzotriazole, 5-butylsulfonyl-2-(2-hydroxy-3,5-di-.alpha.-cumylphenyl)-2H-benzotriazole- , 5-butylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole, 5-butylsulfonyl-2-(2-hydroxy-3,5-di-tert-octylphenyl)-2H-benzotriazole, 5-phenylsulfonyl-2-(2-hydroxy-3,5-di-tert-butylphenyl)-2H-benzotriazole, or 5-chloro-2-(2-hydroxy-3,5-di-a-cumylphenyl)-2H-benzotriazole. Continue reading... Full patent description for Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof or other areas of interest. ### Previous Patent Application: Bonding perfluoroelastomers to aluminum Next Patent Application: Coating and developing system Industry Class: Adhesive bonding and miscellaneous chemical manufacture ### FreshPatents.com Support Thank you for viewing the Ultraviolet protective dual layer laminate for polycarbonate resin substrates and method of manufacture thereof patent info. IP-related news and info Results in 10.76341 seconds Other interesting Feshpatents.com categories: Canon USA , Celera Genomics , Cephalon, Inc. , Cingular Wireless , Clorox , Colgate-Palmolive , Corning , Cymer , |
||
